Article and method for making same

ABSTRACT

An article includes a layer including a melt processable fluoropolymer, wherein the fluoropolymer includes a copolymer of a tetrafluoroethylene and a perfluoroether, wherein the article has an ultraviolet transmittance of at least about 50% at a thickness of about 0.040 inches to about 0.062 inches when exposed to ultraviolet radiation of about 200 nm to about 280 nm. Further provided is a method of making the article and an apparatus for purifying water including an article, such as a flexible tube.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority under 35 U.S.C. §119(e) to U.S. PatentApplication No. 62/288,050, entitled “FLEXIBLE TUBE AND METHODS FORMAKING SAME,” by Timothy J. MORRIS et al., filed Jan. 28, 2016, which isassigned to the current assignee hereof and incorporated herein byreference in its entirety.

FIELD OF THE DISCLOSURE

This application in general, relates to an article and method for makingsame, and in particular, relates to a flexible tube for fluid conduits.

BACKGROUND

Hoses and tubing are used in a variety of industries including watertreatment, food processing, chemical industries, pharmaceuticalindustries, and fuel industries. In such industries, fluid conduits thathave a low surface energy inner surface are used because they are easyto clean and resistant to contaminants. In particular, such industriesare turning to low surface energy polymers such as fluoropolymers.However, such fluoropolymers are expensive and often have undesirableproperties for certain applications.

In particular, industry uses such fluoropolymers for fluid conduits forwater treatment. However, many fluoropolymers do not have theultraviolet transmittance properties desired to treat and purify waterat desirable ultraviolet wavelengths. Further, many fluoropolymers alsoare inflexible, making the material undesirable for applications thatrequire stress, such as bend radius, pressures, and the like.

As such, an improved flexible tube would be desirable.

SUMMARY

In an embodiment, an article includes a layer including a meltprocessable fluoropolymer, wherein the fluoropolymer includes acopolymer of a tetrafluoroethylene and a perfluoroether, wherein thearticle has an ultraviolet transmittance of at least about 50% whenmeasured at a thickness of about 0.040 inches to about 0.062 inches whenexposed to ultraviolet radiation of about 200 nm to about 280 nm.

In another embodiment, a method of making an article includes providinga layer including a melt processable fluoropolymer, wherein thefluoropolymer includes a copolymer of a tetrafluoroethylene and aperfluoroether, wherein the article has an ultraviolet transmittance ofat least about 50% when measured at a thickness of about 0.040 inches toabout 0.062 inches when exposed to ultraviolet radiation of about 200 nmto about 280 nm.

In yet another embodiment, an apparatus for purifying water includes asource of ultraviolet radiation; and a flexible tube, the flexible tubeincluding a layer including a melt processable fluoropolymer, whereinthe fluoropolymer includes a copolymer of a tetrafluoroethylene and aperfluoroether, wherein the flexible tube has an ultraviolettransmittance of at least about 50% when measured at a thickness ofabout 0.040 inches to about 0.062 inches when exposed to ultravioletradiation of about 200 nm to about 280 nm.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The following description in combination with the figures is provided toassist in understanding the teachings disclosed herein. The followingdiscussion will focus on specific implementations and embodiments of theteachings. This focus is provided to assist in describing the teachingsand should not be interpreted as a limitation on the scope orapplicability of the teachings.

As used herein, the terms “comprises”, “comprising”, “includes”,“including”, “has”, “having” or any other variation thereof, areopen-ended terms and should be interpreted to mean “including, but notlimited to . . . .” These terms encompass the more restrictive terms“consisting essentially of” and “consisting of.” In an embodiment, amethod, article, or apparatus that comprises a list of features is notnecessarily limited only to those features but may include otherfeatures not expressly listed or inherent to such method, article, orapparatus. Further, unless expressly stated to the contrary, “or” refersto an inclusive-or and not to an exclusive-or. For example, a conditionA or B is satisfied by any one of the following: A is true (or present)and B is false (or not present), A is false (or not present) and B istrue (or present), and both A and B are true (or present).

Also, the use of “a” or “an” is employed to describe elements andcomponents described herein. This is done merely for convenience and togive a general sense of the scope of the invention. This descriptionshould be read to include one or at least one and the singular alsoincludes the plural, or vice versa, unless it is clear that it is meantotherwise. For example, when a single item is described herein, morethan one item may be used in place of a single item. Similarly, wheremore than one item is described herein, a single item may be substitutedfor that more than one item.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The materials, methods, andexamples are illustrative only and not intended to be limiting. To theextent not described herein, many details regarding specific materialsand processing acts are conventional and may be found in reference booksand other sources within the structural arts and correspondingmanufacturing arts. Unless indicated otherwise, all measurements are atabout 23° C.+/−5° C. per ASTM, unless indicated otherwise.

In a particular embodiment, an article is provided. The article includesa layer including a fluoropolymer. In an embodiment, the article is aflexible tube. Advantageously, the article has desirable properties forapplications such as water treatment via ultraviolet radiation. A methodof making the article is further provided. An apparatus for purifyingwater with the flexible tube is also provided.

The fluoropolymer of the layer of the article typically is a meltprocessable fluoropolymer. “Melt processable fluoropolymer” as usedherein refers to a fluoropolymer that can melt and flow to extrude inany reasonable form such as films, tubes, fibers, molded articles, orsheets. For instance, the melt processable fluoropolymer is a flexiblematerial. For instance, the melt processable fluoropolymer has aflexural modulus of at least about 400 MPa, such as about 400 MPa toabout 1000 MP, such as about 500 MPa to about 800 MPa, such as about 500MPa to about 650 MPa. In an embodiment, the melt processablefluoropolymer has a tensile yield of about 0.5% to about 15%, such asabout 1% to about 15%, such as about 1% to about 10%. In a particularembodiment, the melt processable fluoropolymer has a desirable hardness.For instance, the shore hardness of the fluoropolymer of the layer is ashore D of less than about 90, such as less than about 80, or even lessthan about 70. In an embodiment, the shore D hardness of thefluoropolymer layer is about 50 to about 60. It will be appreciated thatthe flexural modulus, tensile yield, and shore D hardness of thefluoropolymer layer can be within a range between any of the minimum andmaximum values noted above.

Any reasonable melt processable fluoropolymer is envisioned. Anexemplary melt processable fluoropolymer for the article may be formedof a homopolymer, copolymer, terpolymer, or polymer blend formed from amonomer, such as tetrafluoroethylene, hexafluoropropylene,chlorotrifluoroethylene, trifluoroethylene, vinylidene fluoride, vinylfluoride, perfluoropropyl vinyl ether, perfluoromethyl vinyl ether, orany combination thereof. An exemplary melt processable fluoropolymerincludes a copolymer of tetrafluoroethylene and a perfluoroether. In anembodiment, the perfluoroether may be a perfluoroalkyl vinyl ether(PAVE). Any alkyl group is envisioned for the perfluoroalkyl vinylether. In a particular embodiment, the perfluoroalkyl vinyl ether is aperfluoromethyl vinyl ether, a perfluoroethyl vinyl ether, aperfluoropropyl vinyl ether, a blend, or combination thereof. In anexemplary embodiment, the melt processable fluoropolymer is a copolymerof a tetrafluoroethylene and a perfluoropropyl vinyl ether, a copolymerof a tetrafluoroethylene and a perfluoromethyl vinyl ether, a copolymerof a tetrafluoroethylene and a perfluoroethyl vinyl ether, a blend, orany combination thereof. In a particular embodiment, the copolymer oftetrafluoroethylene and perfluoroether includes an advantageous weightpercent ratio of about 2% to about 12%, such as about 3% to about 10%,or about 4% to about 8%. It will be appreciated that the molarconcentration ratio can be within a range between any of the minimum andmaximum values noted above. In an embodiment, the melt processablefluoropolymer is substantially free of hexafluoropropylene.“Substantially free” as used herein refers to less than about 1.0% byweight, or even less than about 0.1% by weight of the total weight ofthe fluoropolymer.

In a further embodiment, the layer may include any additive envisioned.The additive may include, for example, a co-agent, an antioxidant, afiller, an ultraviolet (UV) agent, a dye, a pigment, an anti-agingagent, a plasticizer, the like, or combination thereof. In anembodiment, the use of a co-agent may provide desirable properties suchas decreased permeation of small molecules and improved elastic recoveryof the layer compared to a layer that does not include a co-agent. Anyco-agent is envisioned such as, for example, bis-phenol AF, triarylisocyanurate (TAIC), Triaryl cyanurate (TAC), an organic peroxide, orcombination thereof. Alternatively, the layer may be substantially freeof a co-agent, an antioxidant, a filler, an ultraviolet (UV) agent, adye, a pigment, an anti-aging agent, a plasticizer, or a combinationthereof. “Substantially free” as used herein refers to less than about1.0% by weight, or even less than about 0.1% by weight of the totalweight of the fluoropolymer.

In an embodiment, the article may further include an additional polymerthat does not adversely affect the ultraviolet transmission propertiesof the fluoropolymer. In an embodiment, the additional polymer has anultraviolet transmittance of at least about 50%, such as at least about60%, or even greater than about 65% at a wavelength of 200 nm to about280 nm when measured at a thickness as described. For instance, theadditional polymer may be polyvinyl chloride (PVC), polyethyleneterephthalate (PET), polypropylene (PP), polyethylene (PE),polycarbonate (PC), polymethyl methacrylate (PMMA), acrylic, cyclicolefin copolymer (COC), a blend, or combination thereof. In a particularembodiment, the layer includes at least 70% by weight of thefluoropolymer. For example, the layer may include at least 85% by weightfluoropolymer, such as at least 90% by weight, at least 95% by weight,or even 100% by weight of the fluoropolymer. In an example, the layermay consist essentially of the fluoropolymer. As used herein, the phrase“consists essentially of” used in connection with the fluoropolymer ofthe layer of the article precludes the presence of non-fluorinatedpolymers that affect the basic and novel characteristics of thefluoropolymer, although, commonly used processing agents and additivessuch as an antioxidant, a fillers, a UV agent, a dye, a pigment, ananti-aging agent, and any combination thereof may be used in thefluoropolymer. In a more particular embodiment, the fluoropolymerconsists essentially of the copolymer of the tetrafluoroethylene and theperfluoroether, such as the perfluoroalkyl vinyl ether. In an example,the layer may consist of the fluoropolymer. As used herein, the phrase“consists of” used in connection with the fluoropolymer of the layerprecludes the presence of any other components within the layer. In amore particular embodiment, the fluoropolymer consists of the copolymerof the tetrafluoroethylene and the perfluoroether, such as theperfluoroalkyl vinyl ether.

The article may have an advantageous ultraviolet transmittance. Forinstance, the article has an ultraviolet transmittance of at least about50% when measured at a thickness of the article of about 0.040 inches toabout 0.062 inches when exposed to ultraviolet radiation of about 200nanometers(nm) to about 280 nm. “Thickness” as used herein refers to thewall thickness of the fluoropolymer layer. In an embodiment, thethickness of the fluoropolymer layer may be between about 0.0005 inchesand about 0.125 inches. In an embodiment, the article has an ultraviolettransmittance of at least about 60%, or at least about 65%, whenmeasured at a thickness of about 0.040 inches to about 0.062 inches whenexposed to ultraviolet radiation of about 200 nm to about 280 nm. In anembodiment, any thickness of the article is envisioned, with the provisothat the ultraviolet transmittance is at least about 50% when exposed toultraviolet radiation of about 200 nm to about 280 nm. It will beappreciated that the thickness of the fluoropolymer layer can be withina range between any of the minimum and maximum values noted above. In anembodiment, the article consists essentially of the fluoropolymer layeras described. In a more particular embodiment, the article consists ofthe fluoropolymer layer as described.

Although described as one layer, in an alternative embodiment any numberof layers is envisioned. For instance, the article includes at least twolayers, or even a greater number of layers. The number of layers isdependent upon the final properties desired for the article. In anembodiment, the article may further include other layers. Other layersinclude, for example, a polymeric layer, a reinforcing layer, anadhesive layer, a barrier layer, a chemically resistant layer, anycombination thereof, and the like, with the proviso that the article hasan advantageous ultraviolet transmittance as described above. Anyreasonable method of providing any additional layer is envisioned and isdependent upon the material chosen. Any thickness of the other layersmay be envisioned. In an embodiment, the total thickness of the articlemay be at least 0.0005 inches to about 0.250 inches. It will beappreciated that the total thickness of the article can be within arange between any of the minimum and maximum values noted above.

In an embodiment, the article may be formed by any reasonable means andis dependent upon the material chosen and the final article desired. Inan example, the layer of the fluoropolymer is provided by any reasonablemeans. In an embodiment, the fluoropolymer is formed by extrusion orinjection molding. In an embodiment, the fluoropolymer is formed with anextrusion system. The extrusion system typically includes a pumpingsystem and can include a number of devices that can be utilized to formthe layer of the article. For example, the pumping system can include apumping device such as a gear pump, a static mixer, an extruder, a die,such as a tube die, a cure device, a post-processing device, or anycombination thereof. Typically, the fluoropolymer material is mixed andpumped, i.e. extruded, through the die of the extrusion system. Anyreasonable mixing apparatus is envisioned. In an embodiment, heat mayalso be applied to the fluoropolymer material. For instance, anyreasonable heating temperature for the components of the fluoropolymermaterial may be used to provide a material that can flow from thepumping system and extruded through the die without degradation of thematerial. For instance, the temperature may be about 250° C. to about420° C. It will be appreciated that the heating temperature can bewithin a range between any of the minimum and maximum values notedabove. In an exemplary embodiment, the die is configured to provide anextruded article with any dimension or shape envisioned. In a particularembodiment, the tube die is configured to provide an extruded tube witha circular shape; however, any dimension or shape is envisioned.

In an embodiment, the article is cooled after extrusion. Any method ofcooling the article is envisioned. In an embodiment, the article iscooled at a temperature that is less than a melting temperature of thefluoropolymer. In a particular embodiment, the article is cooled at atemperature of about 1° C. to about 99° C., such as about 1° C. to about70° C., or about 70° C. to 99° C. In a particular embodiment, thearticle is sprayed with aerosolized water. In a more particularembodiment, the aerosolized water is at a temperature of about 1° C. toabout 99° C., such as about 1° C. to about 25° C. In an embodiment, thearticle is placed in a liquid having a temperature lower than roomtemperature, for instance, water at a temperature of less than 25° C.Any pressure of the aerosolized water is envisioned. In an embodiment,the pressure of the aerosolized water is at least about 0.1 barr, suchas about 0.1 barr to about 10 barr. It will be appreciated that thewater temperature and pressure can be within a range between any of theminimum and maximum values noted above.

Once the layer is formed, the article can undergo one or more postprocessing operations. Any reasonable post processing operations areenvisioned. For instance, the article can be subjected to any radiationtreatment, such as UV radiation, e-beam radiation, gamma radiation, andthe like. Further, the article can be subjected to a post-processingthermal treatment. The post-processing thermal treatment typicallyoccurs at a temperature of about 1° C. to about 250° C. Typically, thepost thermal treatment occurs for a time period of about 5 minutes toabout 10 hours, such as about 10 minutes to about 30 minutes, oralternatively about 1 hour to about 4 hours. It will be appreciated thatthe post thermal treatment temperature and time can be within a rangebetween any of the minimum and maximum values noted above. In analternative example, the article is not subjected to a post thermaltreatment. In an example, the article is a flexible tube that can be cutinto a number of flexible tubes having a specified length. In anotherembodiment, the post processing can include wrapping the flexible tubeinto a coil of tubing.

In an embodiment, the article is a flexible tube that includes an innersurface that defines a central lumen of the tube. For instance, theflexible tube may be provided that has any useful diameter size for theparticular application chosen. In an embodiment, the tubing may have anoutside diameter (OD) of up to about 5.0 inches, such as about 0.25inch, 0.50 inch, and 1.0 inch. In an embodiment, the tubing may have aninside diameter (ID) of about 0.03 inches to about 4.00 inches, such asabout 0.06 inches to about 1.00 inches. It is envisioned that theoutside diameter and the inside diameter may be within the minimum andmaximum values described.

In embodiment, the resulting article may have further desirable physicaland mechanical properties. In an embodiment, the article has opticalclarity. In an embodiment, the article appears transparent or at leasttranslucent. For instance, the article may have a light transmissiongreater than about 50%, greater than about 75%, or greater than about99% in the visible light wavelength range. In particular, the articlehas desirable flexibility and substantial clarity or translucency. In anembodiment, the article has a desirable crystallinity. Although not tobe bound by theory, the crystallinity of the fluoropolymer providesoptical clarity and advantageous ultraviolet transmittance. Forinstance, the fluoropolymer has a crystallinity of less about 50%, suchas less than about 30%, less than about 20%, or less than about 10%. Inan embodiment, the fluoropolymer has a crystallinity of about 1% toabout 75%, such as about 1% to about 50%, such as about 1% to about 40%,such as about 1% to about 30%.

Although generally described as an article, such as a flexible tube, anyreasonable polymeric article can be envisioned. The polymeric articlemay alternatively take the form of a film, a washer, a container, or afluid conduit. For example, the polymeric article may take the form or afilm, such as a laminate, or a planar article, such as a septa or awasher. In another example, the polymeric article may take the form of afluid conduit, such as tubing, a pipe, a hose or more specificallyflexible tubing, transfer tubing, pump tubing, chemical resistanttubing, high purity tubing, reinforced tubing, braided tubing, smoothbore tubing, fluoropolymer lined pipe, or rigid pipe, or any combinationthereof. In a particular embodiment, a flexible tube is a watertreatment tube, a peristaltic pump tube, such as for chemical ordetergent dispensing, or a liquid transfer tube, such as a chemicallyresistant liquid transfer tube.

Applications for the article are numerous. In an exemplary embodiment,the article may be used in applications such as water treatment,industrial, wastewater or other applications where desirable UVtransmittance, and/or chemical resistance, and/or low permeation togases, and/or high purity are desired.

In an embodiment, the article is used with an apparatus for purifyingwater. For instance, the apparatus includes an ultraviolet source andthe article, such as a flexible tube. Water flows through the innerconduit of the flexible tube by any reasonable means. In an embodiment,a pump is used with the apparatus to move the water from a proximal endof the flexible tube to a distal end of the flexible tube. Any lengthbetween the proximal end and the distal end is envisioned. Any flow rateis envisioned to provide water substantially free of a microorganism. Inan embodiment, the flow rate is dependent upon several factors such as,for example, the diameter of the flexible tube, the thickness of theflexible tube, the ultraviolet source, the proximity of the ultravioletsource to the flexible tube, the type of microorganism being irradiated,and the like. “Microorganism” as used herein refers to bacteria, yeast,mold, algae, a virus, the like, or combination thereof.

As the water flows from the proximal end of the article to the distalend of the article, the water within the article is exposed to theultraviolet source. Any ultraviolet source is envisioned along anylength of the article. In an embodiment, the ultraviolet source is a “C”type providing radiation in a wavelength of about 200 nm to about 280nm. Any time for exposure is envisioned. In an embodiment, the time forexposure is dependent upon flow rate of the water, amount ofmicroorganism present before irradiation with the ultraviolet source,the proximity of the ultraviolet source to the article, the type ofmicroorganism, the ultraviolet source, the thickness of the article, thediameter of the article when it is, for example, a flexible tube, thelike, or combination thereof. Any reasonable time is envisioned such as1 second to 10 minutes, such as 1 second to 5 minutes, such as 20seconds to 2 minutes, or even 1 minute to 5 minutes. In an embodiment,the water is substantially free of a microorganism after exposure to theultraviolet radiation. “Substantially free” as used herein refers toless than about 0.1%, or even less than 0.01% of a microorganism.

Many different aspects and embodiments are possible. Some of thoseaspects and embodiments are described herein. After reading thisspecification, skilled artisans will appreciate that those aspects andembodiments are only illustrative and do not limit the scope of thepresent invention. Embodiments may be in accordance with any one or moreof the items as listed below.

Embodiment 1

An article includes a layer including a melt processable fluoropolymer,wherein the fluoropolymer includes a copolymer of a tetrafluoroethyleneand a perfluoroether, wherein the article has an ultraviolettransmittance of at least about 50% when measured at a thickness ofabout 0.040 inches to about 0.062 inches when exposed to ultravioletradiation of about 200 nm to about 280 nm.

Embodiment 2

A method of making an article includes providing a layer including amelt processable fluoropolymer, wherein the fluoropolymer includes acopolymer of a tetrafluoroethylene and a perfluoroether, wherein thearticle has an ultraviolet transmittance of at least about 50% whenmeasured at a thickness of about 0.040 inches to about 0.062 inches whenexposed to ultraviolet radiation of about 200 nm to about 280 nm.

Embodiment 3

The article or the method of making the article of any of the precedingembodiments, wherein the copolymer of tetrafluoroethylene and theperfluoroether are present at a weight percent ratio of about 2% toabout 12%, such as about 3% to about 10%, or about 4% to about 8%.

Embodiment 4

The article or the method of making the article of any of the precedingembodiments, wherein the melt processable fluoropolymer consistsessentially of the copolymer of the tetrafluoroethylene and theperfluoroether.

Embodiment 5

The article or the method of making the article of any of the precedingembodiments, wherein the melt processable fluoropolymer consists of thecopolymer of the tetrafluoroethylene and the perfluoroether.

Embodiment 6

The article or the method of making the article of any of the precedingembodiments, wherein the perfluoroether includes perfluoropropyl vinylether, perfluoromethyl vinyl ether, perfluoroethyl vinyl ether, orcombination thereof.

Embodiment 7

The article or the method of making the article of any of the precedingembodiments, wherein the article has a shore D durometer of less thanabout 90, such as about 50 to about 60.

Embodiment 8

The article or the method of making the article of any of the precedingembodiments, wherein the article has a total thickness of about 0.0005inches to about 0.250 inches.

Embodiment 9

The article or the method of making the article of any of the precedingembodiments, wherein the fluoropolymer has optical clarity.

Embodiment 10

The article or the method of making the article of any of the precedingembodiments, wherein the article has an ultraviolet transmittance of atleast about 55%, at least about 60%, or at least about 65%.

Embodiment 11

The article or the method of making the article of any of the precedingembodiments, wherein the melt processable fluoropolymer has acrystallinity of at least about 1%, such as about 1% to about 75%, suchas about 1% to about 50%, such as about 1% to about 40%, such as about1% to about 30%.

Embodiment 12

The article or the method of making the article of any of the precedingembodiments, wherein the article has an inner surface providing aconduit for a fluid.

Embodiment 13

The article or the method of making the article of embodiment 12,wherein the fluid is water.

Embodiment 14

The article or the method of making the article of any of the precedingembodiments, wherein the article has a flexural modulus of at leastabout 400 MPa, such as about 500 MPa to about 650 MPa.

Embodiment 15

The article or the method of making the article of any of the precedingembodiments, wherein the melt processable fluoropolymer has a tensileyield of about 0.5% to about 15%, such as about 1% to about 15%, such asabout 1% to about 10%.

Embodiment 16

The method of making the article of any of the preceding embodiments,wherein providing the layer includes extruding the melt processablefluoropolymer.

Embodiment 17

The method of making the article of embodiment 16, further includingcooling the article at a temperature of about 1° C. to about 99° C.

Embodiment 18

An apparatus for purifying water includes a source of ultravioletradiation; and a flexible tube, the flexible tube including a layerincluding a melt processable fluoropolymer, wherein the fluoropolymerincludes a copolymer of a tetrafluoroethylene and a perfluoroether,wherein the flexible tube has an ultraviolet transmittance of at leastabout 50% when measured at a thickness of about 0.040 inches to about0.062 inches when exposed to ultraviolet radiation of about 200 nm toabout 280 nm.

Embodiment 19

The apparatus of embodiment 18, wherein the source of ultravioletradiation is at a wavelength of about 200 nm to about 280 nm.

Embodiment 20

The apparatus of embodiments 18-19, wherein the copolymer oftetrafluoroethylene and the perfluoroether are present at a weightpercent ratio of about 2% to about 12%, such as about 3% to about 10%,or about 4% to about 8%.

Embodiment 21

The apparatus of embodiments 18-20, wherein the melt processablefluoropolymer consists essentially of the copolymer of thetetrafluoroethylene and the perfluoroether.

Embodiment 22

The apparatus of embodiments 18-21, wherein the melt processablefluoropolymer consists of the copolymer of the tetrafluoroethylene andthe perfluoroether.

Embodiment 23

The apparatus of embodiments 18-22, wherein the perfluoroether includesperfluoropropyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethylvinyl ether, or combination thereof.

Embodiment 24

The apparatus of embodiments 18-23, wherein the flexible tube has ashore D durometer of less than about 90, such as about 50 to about 60.

Embodiment 25

The apparatus of embodiments 18-24, wherein the tube has a totalthickness of about 0.0005 inches to about 0.250 inches.

Embodiment 26

The apparatus of embodiments 18-25, wherein the fluoropolymer hasoptical clarity.

Embodiment 27

The apparatus of embodiment 18-26, wherein the flexible tube has anultraviolet transmittance of at least about 55%, at least about 60%, atleast about 65% or even greater.

Embodiment 28

The apparatus of embodiments 18-27, wherein the melt processablefluoropolymer has a crystallinity of at least about 1%, such as about 1%to about 75%, such as about 1% to about 50%, such as about 1% to about40%, such as about 1% to about 30%.

Embodiment 29

The apparatus of embodiments 18-28, wherein the flexible tube has aninner surface providing a conduit for the water.

Embodiment 30

The apparatus of embodiment 29, wherein the water is substantially freeof a microorganism.

The concepts described herein will be further described in the followingexamples, which do not limit the scope of the disclosure described inthe claims. The following examples are provided to better disclose andteach processes and compositions of the present invention. They are forillustrative purposes only, and it must be acknowledged that minorvariations and changes can be made without materially affecting thespirit and scope of the invention as recited in the claims that follow.

EXAMPLES

Several tubes are formed using varying resins and two differentprocessing conditions. The three different resin options 1, 2, and 3 areeach a copolymer of a tetrafluoroethylene and a perfluoroalkyl vinylether. These tubes are compared to a baseline (Tube 5) of FEP(fluorinated ethylene propylene resin). The FEP is a copolymer oftetrafluoroethylene and hexafluoropropylene or a terpolymer oftetrafluoroethylene, hexafluoropropylene, and perfluoroalkyl vinylether.

Two different process conditions were used. The melt processablefluoropolymer is melted and then tubes are extruded and cooled either ata temperature above 70° F. (process A) or below 70° F. (process B).

The tubing had a wall thickness of 0.045 inches and UV transmission ismeasured at wavelengths from 200 nm to 295 nm. Results can be seen inTable 1:

TABLE 1 Baseline TUBE 5 TUBE 6 TUBE 7 TUBE 8 TUBE 9 TUBE 11 TUBE 10Wavelength Transmission Baseline Option Option Option Option OptionOption (nanometer) (%) A 3B 3A 2B 2A 1B 1A 200.00 101.43 21.45 56.8951.08 56.44 51.87 46.66 47.72 205.00 102.50 20.28 53.78 48.29 53.3649.03 44.11 45.11 210.00 101.50 21.11 58.84 53.12 58.29 51.04 45.9246.96 215.00 101.14 25.88 62.99 57.22 61.27 54.75 50.52 51.98 220.00100.57 30.30 65.32 59.67 64.44 57.92 54.64 56.04 225.00 99.55 34.9667.33 62.08 66.50 60.34 58.34 59.29 230.00 99.56 39.51 69.35 64.25 68.1562.44 61.31 61.89 235.00 99.23 43.70 70.41 65.33 69.04 63.91 63.24 64.03240.00 99.76 47.80 71.31 66.41 69.89 65.17 65.06 65.75 245.00 99.7151.16 71.84 67.12 70.32 65.71 66.09 66.93 250.00 99.79 53.55 71.58 67.0070.00 65.80 66.54 67.10 255.00 100.02 55.49 71.31 67.09 70.04 65.6266.97 67.46 260.00 100.01 57.34 71.55 67.40 70.37 65.85 67.72 68.22265.00 99.75 59.23 72.27 68.08 70.92 66.60 68.70 69.09 270.00 99.8560.89 72.89 68.81 71.64 67.26 69.82 70.23 275.00 99.78 62.28 73.56 69.7572.39 68.00 70.72 71.26 280.00 99.79 63.73 74.37 70.43 73.30 68.86 71.7172.29 285.00 99.86 64.84 74.85 71.17 73.87 69.45 72.55 72.96 290.0099.78 65.65 75.27 71.81 74.36 69.95 73.16 73.67 295.00 99.77 66.41 75.7672.15 74.84 70.41 73.87 74.10

Clearly, Options 1, 2, and 3 all have improved UV transmission acrossall wavelength values compared to the baseline tube (FEP). Further, theprocess using the lower cooling temperature shows an improvement in UVtransmission for both Options 1 and 2.

Note that not all of the activities described above in the generaldescription or the examples are required, that a portion of a specificactivity may not be required, and that one or more further activitiesmay be performed in addition to those described. Still further, theorder in which activities are listed are not necessarily the order inwhich they are performed.

In the foregoing specification, the concepts have been described withreference to specific embodiments. However, one of ordinary skill in theart appreciates that various modifications and changes can be madewithout departing from the scope of the invention as set forth in theclaims below. Accordingly, the specification and figures are to beregarded in an illustrative rather than a restrictive sense, and allsuch modifications are intended to be included within the scope ofinvention.

Benefits, other advantages, and solutions to problems have beendescribed above with regard to specific embodiments. However, thebenefits, advantages, solutions to problems, and any feature(s) that maycause any benefit, advantage, or solution to occur or become morepronounced are not to be construed as a critical, required, or essentialfeature of any or all the claims.

After reading the specification, skilled artisans will appreciate thatcertain features are, for clarity, described herein in the context ofseparate embodiments, may also be provided in combination in a singleembodiment. Conversely, various features that are, for brevity,described in the context of a single embodiment, may also be providedseparately or in any subcombination. Further, references to valuesstated in ranges include each and every value within that range.

What is claimed is:
 1. An article comprises: a layer comprising a meltprocessable fluoropolymer, wherein the fluoropolymer comprises acopolymer of a tetrafluoroethylene and a perfluoroether, wherein thearticle has an ultraviolet transmittance of at least about 50% whenmeasured at a thickness of about 0.040 inches to about 0.062 inches whenexposed to ultraviolet radiation of about 200 nm to about 280 nm.
 2. Thearticle of claim 1, wherein the copolymer of tetrafluoroethylene and theperfluoroether are present at a weight percent ratio of about 2% toabout 12%, such as about 3% to about 10%, or about 4% to about 8%. 3.The article of claim 1, wherein the perfluoroether comprisesperfluoropropyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethylvinyl ether, or combination thereof.
 4. The article of claim 1, whereinthe melt processable fluoropolymer consists essentially of the copolymerof the tetrafluoroethylene and the perfluoroether.
 5. The article ofclaim 1, wherein the article has a shore D durometer of less than about90, such about 50 to about
 60. 6. The article of claim 1, wherein thearticle has a total thickness of about 0.0005 inches to about 0.250inches.
 7. The article of claim 1, wherein the article has an innersurface providing a conduit for a fluid.
 8. The article of claim 7,wherein the fluid is water.
 9. A method of making an article comprises:providing a layer comprising a melt processable fluoropolymer, whereinthe fluoropolymer comprises a copolymer of a tetrafluoroethylene and aperfluoroether, wherein the article has an ultraviolet transmittance ofat least about 50% when measured at a thickness of about 0.040 inches toabout 0.062 inches when exposed to ultraviolet radiation of about 200 nmto about 280 nm.
 10. The method of making the article of claim 9,wherein providing the layer comprises extruding the melt processablefluoropolymer.
 11. The method of making the article of claim 10, furthercomprising cooling the article at a temperature of about 1° C. to about99° C.
 12. The method of making the article of claim 9, wherein theperfluoroether comprises perfluoropropyl vinyl ether, perfluoromethylvinyl ether, perfluoroethyl vinyl ether, or combination thereof.
 13. Themethod of making the article of claim 9, wherein the melt processablefluoropolymer consists essentially of the copolymer of thetetrafluoroethylene and the perfluoroether.
 14. An apparatus forpurifying water comprises: a source of ultraviolet radiation; and aflexible tube, the flexible tube comprising a layer comprising a meltprocessable fluoropolymer, wherein the fluoropolymer comprises acopolymer of a tetrafluoroethylene and a perfluoroether, wherein theflexible tube has an ultraviolet transmittance of at least about 50%when measured at a thickness of about 0.040 inches to about 0.062 incheswhen exposed to ultraviolet radiation of about 200 nm to about 280 nm.15. The apparatus of claim 14, wherein the source of ultravioletradiation is at a wavelength of about 200 nm to about 280 nm.
 16. Theapparatus of claim 14, wherein the perfluoroether comprisesperfluoropropyl vinyl ether, perfluoromethyl vinyl ether, perfluoroethylvinyl ether, or combination thereof.
 17. The apparatus of claim 14,wherein the melt processable fluoropolymer consists essentially of thecopolymer of the tetrafluoroethylene and the perfluoroether.
 18. Theapparatus of claim 14, wherein the tube has a total thickness of 0.0005inches to about 0.250 inches.
 19. The apparatus of claim 14, wherein theflexible tube has an inner surface providing a conduit for the water.20. The apparatus of claim 19, wherein the water is substantially freeof a microorganism after exposure to ultraviolet radiation of about 200nm to about 280 nm.